Free online calculators that show their working
Mortgage, loan, savings, BMI, calories, percentages, dates and unit conversions. Each tool explains the formula, walks through an example and answers common questions.
Finance
Mortgage Calculator
Monthly payment, extra payments and a full amortization table
Loan EMI Calculator
Monthly instalment, total interest and repayment schedule
Compound Interest Calculator
Growth with a starting balance and monthly deposits
Savings Goal Calculator
How much to save each month to reach a target
Health
Everyday
Guides
How Mortgage Payments Work
A plain-English guide to how a mortgage payment is built, why early payments are mostly interest, what escrow adds, and how extra payments change the cost.
How to Read Your BMI Result
What BMI measures, how it is calculated, what the standard categories mean, and when BMI is misleading. A practical guide, not medical advice.
Compound Interest Explained
How compound interest works, with the formula, worked examples, compounding frequency, regular contributions, the Rule of 72 and the effect of inflation.
Why use Numbers Plainly?
- Transparent maths. The formula behind every result is explained on the page, and the calculation code is tested against known values.
- Private. Calculations run in your browser. We do not receive the numbers you enter.
- Shareable. Press “Copy shareable link” on any calculator to save or send your exact inputs.
- Fast and mobile friendly. No sign-up, no downloads, and pages designed to load quickly on a phone.
Calculators are for informational purposes only and are not financial, medical or professional advice. See our disclaimer.